When I was young , air pollution was a major problem , particularly in large cities , much due to automobile exhaust . A government agency (EPA , I think ) . developed a requirement , and had it made into law . The automobile manufacturers had to develop a means of reducing the pollution caused by automobile exhaust . And they DID ! Each car has a kind of filter , sounds like a metal tray full of cat litter to me , that is attached to the exhaust system . While I don't think those ships are going to go back to sails , per se' , I do think they can find a new means of non polluting ,power for them . People are reading a lot about trash accumulating both in the oceans , water ways , and even in landfills . The younger crowd complains about their lower than living wages , and yet are blowing large amounts of cash on things that didn't exist , when I was small . They will , in time , hopefully make the connection , and realize they don't need everything that is being offered for sale . After WWII , there was the baby boom .Today's average family , begins family life later in life , and on average have fewer children . The baby boomer generation is one of the biggest part of the population , As we die out , the number of people will be reduced . Thankfully , we have access to birth control , at least for the baby boomer generation . The government , needs to realize this , and ensure that reliable birth control remains accesible , to all fertile people .

>..a reprise of the venerable sailing ship.

One stuck in the doldrums. It's rare to find a modern sailing ship without a motor.

The technology has not been invented yet they said. It was impressive to me how they are able to read into events and kind of intelligently guess the future.

@St-Sinner well let's hope!